21 November 2014
Obese people put themselves at a higher risk of suffering silent cardiac damage, which can increase the likelihood of them having heart failure in the future, a new study has found.
A team from Johns Hopkins University, Maryland, used an ultrasensitive blood test to detect the presence of a protein that indicates the heart is injured. They found that overweight people without overt heart disease can be at a higher risk of heart failure. This challenges the common belief that cardiac problems are driven by diabetes and high blood pressure in obesity.
Published online on the Journal of the American College of Cardiology: Heart Failure, the research found that obese people suffer from elevated levels of a heart enzyme - troponin T - which is released by heart muscles when they become injured.
High levels of this enzyme corresponded to increases in people's body mass index (BMI), the team found.
For the study, investigators measured the BMIs and levels of troponin in the heart of more than 9,500 heart disease-free men and women. All participants were between 53 and 75 years old and were tracked for more than 12 years. Across this period, 869 people developed heart failure.
Lead investigator Dr Chiadi Ndumele said that obesity is a "well-known 'accomplice' in the development of heart disease", but these new findings suggest that it could be solely responsible for heart failure independent of other risk factors that are commonly found in overweight people.
Dr Ndumele, who is also an assistant professor at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, said: "The direct relationship we found between obesity and subclinical heart damage is quite potent and truly concerning from a public health standpoint given the growing number of obese people in the United States and worldwide."
The team found that severely obese participants, with a BMI of over 35, had more than twice the risk of developing heart failure than people of a normal weight. This escalated risk rose even further the higher the BMI was, growing by 32 per cent for every five-unit increase in BMI.
Anyone with higher troponin levels were deemed to be at an increased risk of having heart failure, regardless of their BMI.
The researchers also discovered that the combination of elevated troponin and severe obesity was significant. Severely obese people with elevated troponin levels were nine times more likely to develop heart failure than people with normal weight and undetectable troponin levels.
The elevated risk persisted even when investigators accounted for other possible causes of heart damage, including diabetes, hypertension and high cholesterol.
"These results are a wake-up call that obesity may further fuel the growing rate of heart failure, and clinicians who care for obese people should not be lulled into a false sense of security by the absence of traditional risk factors, such as high cholesterol, diabetes and hypertension," said Dr Roger Blumenthal, director of the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease. "Obese people, even when free of cardiovascular symptoms, should be monitored for the earliest signs of heart failure and counseled on ways to improve their lifestyle habits."
Posted by Jeanette Royston
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